Woochul Kang

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Environmental wireless sensor network (EWSN) systems are deployed in potentially harsh and remote environments where inevitable node and communication failures must be tolerated. LUSTER---Light Under Shrub Thicket for Environmental Research---is a system that meets the challenges of EWSNs using a hierarchical architecture that includes distributed reliable(More)
Recently, cheap and large capacity non-volatile memory such as flash memory is rapidly replacing disks in embedded systems. While the access time of flash memory is highly predictable, deadline misses may occur if data objects in flash memory are not properly managed in real-time embedded databases. Buffer cache can be used to mitigate this problem.(More)
QeDB (Quality-aware real-time Embedded DataBase) is a database for data-intensive real-time applications running on embedded devices. Currently, databases for embedded systems are best effort, providing no guarantees on their timeliness and data freshness. Existing real-time database (RTDB) technology cannot be applied to these embedded databases since it(More)
Cooperating medical devices, envisioned by Integrated Clinical Environment (ICE) of Medical Device Plug-and-Play (MDPnP), is expected to improve the safety and the quality of patient care. To ensure safety, the cooperating medical devices must be thoroughly verified and tested. However, concurrent control of devices without proper coordination poses a(More)
Medical devices are increasingly capable of interacting with each other by leveraging network connectivity and interoperability, promising a great benefit for patient safety and effectiveness of medical services. However, ad-hoc integration of medical devices through networking can significantly increase the complexity of the system and make the system more(More)
One of the primary requirements in many cyber-physical systems (CPS) is that the sensor data derived from the physical world should be disseminated in a timely and reliable manner to all interested collaborative entities. However, providing reliable and timely data dissemination services is especially challenging for CPS since they often operate in highly(More)
QeDB is a database for data-intensive real-time applications running on flash memory-based embedded systems.Currently, databases for embedded systems are best effort,providing no guarantees on its timeliness and data freshness. Moreover, the existing real-time database (RTDB) technology can not be applied to these embedded databases since they hypothesize(More)
Due to the explosive increases of data from both the cyber and physical worlds, the demand for database support in embedded systems is increasing. Databases for embedded systems, or embedded databases, are expected to provide timely in-situ data services under various resource constraints, such as limited energy. However, traditional buffer cache management(More)
The demand for real-time data services is increasing in many large-scale distributed real-time applications including advanced traffic control, global environment control, and the nation-wide electric power grid control. However, providing quality-of-service (QoS) for data services in such large-scale and geographically distributed environment is a(More)